Nominal Features
Lighting condition
Lighting conditions could be another factor that affects collision, but the population of vehicles under each lighting condition could also be different. We approached the effect of lighting by taking the percentage of the DUI collision rate under each lighting condition and found that DUI collisions are more likely to happen at nighttime in both California and South Dakota.
For example, in South Dakota, approximately 1.4% of collisions that happened during dark times, when the road is lit, are due to DUI. This finding corresponds to section 2.4, that most DUI cases take place on weekend evenings when the day is dark and people might be partying and driving homeward when they collide with someone. There are perhaps fewer people under the influence from early morning and before sunset.
Type of Collision
The most common everyday type of collision would be the rear end, which takes place during high traffic volume hours such as rush hours. That happens to be an unpopular choice in DUI cases when traffic volume is low, but DUI drivers are more likely to hit an object when dark and their senses are impaired.
By the same account of difference in the system, in South Dakota, one would not expect too many roof damages to the car in an everyday collision, rather the front and back of the car in a rear-end, which is also the case in California.
These bars are calculated based on their overall percentage to their own categories, such as (number of DUI cases by category) / (overall number of DUI collisions)
Type of Injury
The bars are generated based on the percentage in their own categories, respectively. Most collisions are only property damage, but DUI has a higher chance of imposing more severe injuries than usual collisions. Similar to South Dakota, DUI tends to cause more severe and fatal injuries than regular cases.
DUI had much more fatal cases before 2018, while the other type of injuries remains relatively unchanged. It is possible that RML raised the awareness of its harm, especially by the increased high fatality rate in the immediate year following RML (2017). Though the consumption level of marijuana is hard to measure for those drivers under influence, people may have opted to smoke less, even when they decided to drive under influence, thus there are fewer fatal injuries.
Compared to California, South Dakota doesn’t appear to have a drastic change in any kind of the injuries listed below: there were no policies implemented that should cause such change. The overall injury rate is also higher, perhaps due to severe winter weather across South Dakota.